I propose to study the function of the mitochondrion in bloodstream and vector forms of trypanosomes. I plan to study this organelle from several points of view: 1) Characterization and functional significance of a branched electron transport system in CN-sensitive trypanosomes; 2) The biosynthesis of mitochondrial enzymes and proteins during the transformation of T. brucei from the bloodstream to the vector form; 3) Presence and function of a DNA-dependent RNA polymerase in the mitochondrion; 4) The action of trypanocidal drugs such as berenil, acriflavine and ethidium bromide on the replication and function of the kinetoplast (mitochondrial) DNA and on the synthesis of the electron transport system. Our major goal is to detect some property in the synthesis or function of the mitochondrion in trypanosomes which will give us a tool for inhibiting the development and replication of these parasites.